diff --git a/include/unistd.h b/include/unistd.h
--- a/include/unistd.h
+++ b/include/unistd.h
@@ -586,6 +586,7 @@
 int	 unwhiteout(const char *);
 void	*valloc(size_t);			/* obsoleted by malloc() */
 int	 funlinkat(int, const char *, int, int);
+pid_t	 _Fork(void);
 
 #ifndef _OPTRESET_DECLARED
 #define	_OPTRESET_DECLARED
diff --git a/lib/libc/sys/Symbol.map b/lib/libc/sys/Symbol.map
--- a/lib/libc/sys/Symbol.map
+++ b/lib/libc/sys/Symbol.map
@@ -417,6 +417,10 @@
 	shm_rename;
 };
 
+FBSD_1.7 {
+	 _Fork;
+};
+
 FBSDprivate_1.0 {
 	___acl_aclcheck_fd;
 	__sys___acl_aclcheck_fd;
diff --git a/lib/libc/sys/fork.2 b/lib/libc/sys/fork.2
--- a/lib/libc/sys/fork.2
+++ b/lib/libc/sys/fork.2
@@ -28,7 +28,7 @@
 .\"	@(#)fork.2	8.1 (Berkeley) 6/4/93
 .\" $FreeBSD$
 .\"
-.Dd April 20, 2021
+.Dd August 2, 2021
 .Dt FORK 2
 .Os
 .Sh NAME
@@ -40,10 +40,12 @@
 .In unistd.h
 .Ft pid_t
 .Fn fork void
+.Ft pid_t
+.Fn _Fork void
 .Sh DESCRIPTION
 The
 .Fn fork
-system call causes creation of a new process.
+function causes creation of a new process.
 The new process (child process) is an exact copy of the
 calling process (parent process) except for the following:
 .Bl -bullet -offset indent
@@ -77,6 +79,15 @@
 All interval timers are cleared; see
 .Xr setitimer 2 .
 .It
+Robust mutexes list (see
+.Xr pthread_mutexattr_setrobust 3 )
+is cleared for the child.
+.It
+The atfork handlers established with
+.Xr pthread_atfork 3
+function are called as appropriate before fork in the parent process,
+and after the child is created, in parent and child.
+.It
 The child process has only one thread,
 corresponding to the calling thread in the parent process.
 If the process has more than one thread,
@@ -87,11 +98,48 @@
 are guaranteed to work in the child process until a call to
 .Xr execve 2
 or a similar function.
+.Fx
+implementation of
+.Fn fork
+provides a usable
+.Xr malloc 3
+and
+.Xr rtld 1
+services in the child process.
 .El
+.Pp
+The
+.Fn fork
+function is not async-signal safe and creates a cancellation point
+in the parent process.
+It cannot be safely used from signal handlers, the atfork handlers
+established by
+.Xr pthread_atfork 3
+do not need to be async-signal safe either.
+.Pp
+The
+.Fn _Fork
+function creates a new process, similarly to
+.Fn fork ,
+but it is async-signal safe.
+.Fn _Fork
+does not call atfork handlers, and does not create a cancellation point.
+It can be used safely from the signal handlers, but then no userspace
+services (
+.Xr malloc 3
+or
+.Xr rtld 1 )
+are available in the child.
+In particular, if using dynamic linking, all dynamic symbols used by the
+child after
+.Fn _Fork
+must be pre-resolved.
 .Sh RETURN VALUES
 Upon successful completion,
 .Fn fork
-returns a value
+and
+.Fn _Fork
+return a value
 of 0 to the child process and returns the process ID of the child
 process to the parent process.
 Otherwise, a value of -1 is returned
@@ -176,9 +224,17 @@
 .Xr setrlimit 2 ,
 .Xr sigaction 2 ,
 .Xr vfork 2 ,
-.Xr wait 2
+.Xr wait 2 ,
+.Xr pthread_atfork 3
 .Sh HISTORY
 The
 .Fn fork
 function appeared in
 .At v1 .
+The
+.Fn _Fork
+function was defined by Austin Group together with dropping a requirement
+that
+.Fn fork
+implementation must be async-signal safe, and it appeared in
+.Fx 14.0 .
diff --git a/lib/libc/sys/fork.c b/lib/libc/sys/fork.c
--- a/lib/libc/sys/fork.c
+++ b/lib/libc/sys/fork.c
@@ -38,6 +38,7 @@
 #include "libc_private.h"
 
 __weak_reference(__sys_fork, __fork);
+__weak_reference(__sys_fork, _Fork);
 
 #pragma weak fork
 pid_t